If you are on a wireless network that's (a) not broadcasting it's SSID, and (b) uses WEP, there's a bunch of matters that'll give you grief. Every time you reboot, you'll lose the airport connection -- even if you have your location set to connect to a specific network, the system just doesn't remember the base station, and re-entering a 128bit HEX key everytime is a pain (copy-paste doesn't work).

To remedy this, install the AirPort 3.2 update from Apple. As far as I can tell, it's not part of Software Update. Then re-create your location with the specific network and key. Now the machine remembers the network, key, etc and the AirPort unhappiness is gone.

I have had this exact problem at work and it has been my single biggest gripe with Panther. Solved at last!!! :) After I installed the update and rebooted, I had no problem connecting to the non-wep-broadcasted network. This will make a bunch of Mac users here very happy. Just for others to note, I have a 12" PB with a clean install of Panther. The software update did not catch this update on its own.